The hitherto-known system of this type comprises a multiplicity of water sprinkling means such as sprinklers disposed in strategical positions, water pipes disposed in or on the ground and connecting said water sprinkling means with a valve means equipped with a solenoid valve built into the water pipe in a position close to each of said water sprinkling means and a control wiring buried underground between said valve means and a control board installed in a control room or the like, with said valve means being opened and closed from said control board.
However, since the control wiring is buried underground in the above conventional system, there is the problem that when water lines are installed in the ground alongside the control wiring, the control wiring is sometimes damaged during the maintenance of the water lines. Moreover, in the case of a golf course, since the control wiring generally extends several kilometers, voltage drops and insulation failures tend to occur and there is consequently the additional drawback that a thunderbolt falling nearby damages the control wiring. Furthermore, when the control wiring is affected by a thunderbolt or other cause, it is very difficult to locate the point of damage because of underground installation so that much time and labor are involved in inspection and repair work.
Developed to overcome the above-mentioned drawbacks of the conventional system, the present invention has as its object to provide an automatic water sprinkler control system which does not require an extensive control wiring and, hence, is completely free from the risk of damage to the wiring which is associated with the maintenance of water piping and, also, from the risk of malfunctioning of control valves which is associated with such damages.
It is a further object of the present invention to provide a system which requires only a short installation time and a short time for additional work if such work becomes necessary after initial installation, and involves little earth-moving work, thus being suitable for installations, such as golf courses, where damages to the ground surface are serious problems.
It is a still further object of the present invention to provide a system wherein the control valves can be operated positively and accurately even if air or dust enters into the pipeline.